Potential applications of Biotin-CF® dye include detection of biotin binding sites and the degree of biotinylation of proteins, and for the measurement of avidin and streptavidin in crude biological samples. In addition, biotin-CF® dye can be used as a polar tracer by microinjection to study the morphology of cells. CF® dyes are Biotium's line of next-generation fluorescent dyes with advantages in brightness, photostability, and conjugate specificity compared to other fluorescent dyes. • Red fluorescent CF®568 dye has excitation/emission at 562/583 nm. • Far-red fluorescent CF®633 dye has excitation/emission at 630/650 nm. • Far-red fluorescent CF®640R dye has excitation/emission at 642/662 nm.